sltermin.c

一个C格式的脚本处理函数库源代码,可让你的C程序具有执行C格式的脚本文件

/* This file contains enough terminfo reading capabilities sufficient for
 * the slang SLtt interface.
 */

/* Copyright (c) 1992, 1999, 2001, 2002, 2003 John E. Davis
 * This file is part of the S-Lang library.
 *
 * You may distribute under the terms of either the GNU General Public
 * License or the Perl Artistic License.
 */

#include "slinclud.h"

#include "slang.h"
#include "_slang.h"

/*
 * The majority of the comments found in the file were taken from the
 * term(4) man page on an SGI.
 */

/* Short integers are stored in two 8-bit bytes.  The first byte contains
 * the least significant 8 bits of the value, and the second byte contains
 * the most significant 8 bits.  (Thus, the value represented is
 * 256*second+first.)  The value -1 is represented by 0377,0377, and the
 * value -2 is represented by 0376,0377; other negative values are illegal.
 * The -1 generally means that a capability is missing from this terminal.
 * The -2 means that the capability has been cancelled in the terminfo
 * source and also is to be considered missing.
 */

static int make_integer (unsigned char *buf)
{
   register int lo, hi;
   lo = (int) *buf++; hi = (int) *buf;
   if (hi == 0377)
     {
	if (lo == 0377) return -1;
	if (lo == 0376) return -2;
     }
   return lo + 256 * hi;
}

/*
 * The compiled file is created from the source file descriptions of the
 * terminals (see the -I option of infocmp) by using the terminfo compiler,
 * tic, and read by the routine setupterm [see curses(3X).]  The file is
 * divided into six parts in the following order:  the header, terminal
 * names, boolean flags, numbers, strings, and string table.
 *
 * The header section begins the file.  This section contains six short
 * integers in the format described below.  These integers are (1) the magic
 * number (octal 0432); (2) the size, in bytes, of the names section; (3)
 * the number of bytes in the boolean section; (4) the number of short
 * integers in the numbers section; (5) the number of offsets (short
 * integers) in the strings section; (6) the size, in bytes, of the string
 * table.
 */

#define MAGIC 0432

/* In this structure, all char * fields are malloced EXCEPT if the
 * structure is SLTERMCAP.  In that case, only terminal_names is malloced
 * and the other fields are pointers into it.
 */
struct _SLterminfo_Type
{
#define SLTERMINFO 1
#define SLTERMCAP  2
   unsigned int flags;

   unsigned int name_section_size;
   char *terminal_names;

   unsigned int boolean_section_size;
   unsigned char *boolean_flags;

   unsigned int num_numbers;
   unsigned char *numbers;

   unsigned int num_string_offsets;
   unsigned char *string_offsets;

   unsigned int string_table_size;
   char *string_table;

};

static char *tcap_getstr (char *, SLterminfo_Type *);
static int tcap_getnum (char *, SLterminfo_Type *);
static int tcap_getflag (char *, SLterminfo_Type *);
static int tcap_getent (char *, SLterminfo_Type *);

static FILE *open_terminfo (char *file, SLterminfo_Type *h)
{
   FILE *fp;
   unsigned char buf[12];

   /* Alan Cox reported a security problem here if the application using the
    * library is setuid.  So, I need to make sure open the file as a normal
    * user.  Unfortunately, there does not appear to be a portable way of
    * doing this, so I am going to use 'setfsgid' and 'setfsuid', which
    * are not portable.
    *
    * I will also look into the use of setreuid, seteuid and setregid, setegid.
    * FIXME: Priority=medium
    */
   fp = fopen (file, "rb");
   if (fp == NULL) return NULL;

   if ((12 == fread ((char *) buf, 1, 12, fp) && (MAGIC == make_integer (buf))))
     {
	h->name_section_size = make_integer (buf + 2);
	h->boolean_section_size = make_integer (buf + 4);
	h->num_numbers = make_integer (buf + 6);
	h->num_string_offsets = make_integer (buf + 8);
	h->string_table_size = make_integer (buf + 10);
     }
   else
     {
	fclose (fp);
	fp = NULL;
     }
   return fp;
}

/*
 * The terminal names section comes next.  It contains the first line of the
 * terminfo description, listing the various names for the terminal,
 * separated by the bar ( | ) character (see term(5)).  The section is
 * terminated with an ASCII NUL character.
 */

/* returns pointer to malloced space */
static unsigned char *read_terminfo_section (FILE *fp, unsigned int size)
{
   char *s;

   if (NULL == (s = (char *) SLmalloc (size))) return NULL;
   if (size != fread (s, 1, size, fp))
     {
	SLfree (s);
	return NULL;
     }
   return (unsigned char *) s;
}

static char *read_terminal_names (FILE *fp, SLterminfo_Type *t)
{
   return t->terminal_names = (char *) read_terminfo_section (fp, t->name_section_size);
}

/*
 * The boolean flags have one byte for each flag.  This byte is either 0 or
 * 1 as the flag is present or absent.  The value of 2 means that the flag
 * has been cancelled.  The capabilities are in the same order as the file
 * <term.h>.
 */

static unsigned char *read_boolean_flags (FILE *fp, SLterminfo_Type *t)
{
   /* Between the boolean section and the number section, a null byte is
    * inserted, if necessary, to ensure that the number section begins on an
    * even byte offset. All short integers are aligned on a short word
    * boundary.
    */

   unsigned int size = (t->name_section_size + t->boolean_section_size) % 2;
   size += t->boolean_section_size;

   return t->boolean_flags = read_terminfo_section (fp, size);
}

/*
 * The numbers section is similar to the boolean flags section.  Each
 * capability takes up two bytes, and is stored as a short integer.  If the
 * value represented is -1 or -2, the capability is taken to be missing.
 */

static unsigned char *read_numbers (FILE *fp, SLterminfo_Type *t)
{
   return t->numbers = read_terminfo_section (fp, 2 * t->num_numbers);
}

/* The strings section is also similar.  Each capability is stored as a
 * short integer, in the format above.  A value of -1 or -2 means the
 * capability is missing.  Otherwise, the value is taken as an offset from
 * the beginning of the string table.  Special characters in ^X or \c
 * notation are stored in their interpreted form, not the printing
 * representation.  Padding information ($<nn>) and parameter information
 * (%x) are stored intact in uninterpreted form.
 */

static unsigned char *read_string_offsets (FILE *fp, SLterminfo_Type *t)
{
   return t->string_offsets = (unsigned char *) read_terminfo_section (fp, 2 * t->num_string_offsets);
}

/* The final section is the string table.  It contains all the values of
 * string capabilities referenced in the string section.  Each string is
 * null terminated.
 */

static char *read_string_table (FILE *fp, SLterminfo_Type *t)
{
   return t->string_table = (char *) read_terminfo_section (fp, t->string_table_size);
}

/*
 * Compiled terminfo(4) descriptions are placed under the directory
 * /usr/share/lib/terminfo.  In order to avoid a linear search of a huge
 * UNIX system directory, a two-level scheme is used:
 * /usr/share/lib/terminfo/c/name where name is the name of the terminal,
 * and c is the first character of name.  Thus, att4425 can be found in the
 * file /usr/share/lib/terminfo/a/att4425.  Synonyms for the same terminal
 * are implemented by multiple links to the same compiled file.
 */

static char *Terminfo_Dirs [] =
{
   NULL, /* $HOME/.terminfo */
   NULL, /* $TERMINFO */
   "/usr/share/terminfo",
   "/usr/lib/terminfo",
   "/usr/share/lib/terminfo",
   "/etc/terminfo",
   "/usr/local/lib/terminfo",
#ifdef MISC_TERMINFO_DIRS
   MISC_TERMINFO_DIRS,
#endif
   ""
};

SLterminfo_Type *_SLtt_tigetent (char *term)
{
   char *tidir;
   int i;
   FILE *fp = NULL;
   char file[1024];
   static char home_ti [1024];
   char *home;
   SLterminfo_Type *ti;

   if (
       (term == NULL)
#ifdef SLANG_UNTIC
       && (SLang_Untic_Terminfo_File == NULL)
#endif
       )
     return NULL;

   if (_SLsecure_issetugid ()
       && ((term[0] == '.') || (NULL != strchr (term, '/'))))
     return NULL;

   if (NULL == (ti = (SLterminfo_Type *) SLmalloc (sizeof (SLterminfo_Type))))
     {
	return NULL;
     }

#ifdef SLANG_UNTIC
   if (SLang_Untic_Terminfo_File != NULL)
     {
	fp = open_terminfo (SLang_Untic_Terminfo_File, ti);
	goto fp_open_label;
     }
   else
#endif
   /* If we are on a termcap based system, use termcap */
   if (0 == tcap_getent (term, ti)) return ti;

   if (NULL != (home = _SLsecure_getenv ("HOME")))
     {
	strncpy (home_ti, home, sizeof (home_ti) - 11);
	home_ti [sizeof(home_ti) - 11] = 0;
	strcat (home_ti, "/.terminfo");
	Terminfo_Dirs [0] = home_ti;
     }

   Terminfo_Dirs[1] = _SLsecure_getenv ("TERMINFO");
   i = 0;
   while (1)
     {
	tidir = Terminfo_Dirs[i];
	if (tidir != NULL)
	  {
	     if (*tidir == 0)
	       break;		       /* last one */

	     if (sizeof (file) > strlen (tidir) + 2 + strlen (term))
	       {
		  sprintf (file, "%s/%c/%s", tidir, *term, term);
		  if (NULL != (fp = open_terminfo (file, ti)))
		    break;
	       }